In the circuit design of a fan, electromagnetic interference (EMI) noise may often interfere with the normal operation of the electrical circuitry of the fan through the fan's power circuit. Hence, the European Telecommunications Standards Institute (ETSI) has formulated many EMI standards for electronic products, wherein the ETSI EN 300 132-2 standard has determined that the low-frequency EMI noise generated by fan circuitry should be below a proscribed level. Therefore, the present disclosure provides a fan with a filter installed in it for filtering out the low-frequency EMI noise generated by the circuit of the fan.